Patch:F10 V Cheat

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The F10 + B or VBL cheat in Keen Galaxy is a cheat. Its purpose is to make the game's graphical output look smooth on old CRT monitors. Adding VBLs helps sync the game's refresh rate to that of the monitors it can be displayed on, preventing the appearance of 'black bars'. A side effect of this is that the game runs slower when more VBLs are added; with 8 VBLs the game runs at 50% speed, 4 runs at 75% speed and so on.


Window

These patches affect the cheat window and text.

Patch: Keen 4
#Add VBLs
%patch $76E8 $0003W
#Window height
%patch $76EC $001EW
#Window width
%patch $76FD $0588W
#Text called from
#Text
%patch $2F3F8 " Add how many extra VBLs(0-8):" $00

Patch: Keen 5
#Add VBLs
%patch $769D $0003W
#Window height
%patch $76A1 $001EW
#Window width
%patch $76B2 $0504W
#Text called from
#Text
%patch $30844 " Add how many extra VBLs(0-8):" $00

Patch: Keen 6
#Add VBLs
%patch $74BD $0003W
#Height
%patch $74C1 $001EW
#Width
%patch $74D2 $0500W
#Text called from
#Text
%patch $31230 " Add how many extra VBLs(0-8):" $00


Key that activates cheat

This patch alters what key activates the VBL cheat. (See Patch:Scancodes.) By default this is 'v' Setting this to $C647, $BCAF or $C7D5 (in Keen 4, Keen 5 and Keen 6 respectively.) will disable the cheat .

Patch: Keen 4
#F10-V key
%patch $76DA $C6A5W

Patch: Keen 5
#F10-V key
%patch $768F $BD0DW

Patch: Keen 5
#F10-V key
%patch $74AF $C833W


Disable

This patch disables the F10 V cheat entirely.

Patch: Keen 4
#Disable Add VBLs (Free $76DB-$7760)
%patch $76D8 $E9 $0086W

Patch: Keen 5
#Disable Add VBLs (Free $7690-$7715)
%patch $768D $E9 $0086W

Patch: Keen 6
#Disable Add VBLs (Free $74B0-$7535)
%patch $74AD $E9 $0086W


Disable F10 - V and F10 - S

As well as disabling F10-V, this disables the F10-S cheat. It frees up significant code space for other patches.

Patch: Keen 4
#Disable F10-S AND F10-V (Free $766B-7760)
%patch $7668 $E9 $00F6W

Patch: Keen 5
#Disable F10-S AND F10-V (Free $761D-7712)
%patch $761D $E9 $00F6W

Patch: Keen 6
#Disable F10-S AND F10-V (Free $7440-7535)
%patch $743D $E9 $00F6W


Cheat gives items

This patch rewrites the cheat to give Keen two kinds of items (Here drops and ammunition, see Patch:Game stats.) This makes it an alternate version of the Items cheat. What items are given and how many can be altered. Note that this patch also frees up some space.

Patch: Keen 4
#F10 V Cheat gives 99 drops and shots, (Free $7722-$7760)
%patch $76D8 $83 $3E $C6A5W $00 $75 $03 $E9 $00EFW $9A $1D060999RL $B8
#Check key
$0003W $50 $B8 $001EW $50 $9A $19311070RL $83 $C4 $04 $B8
#Draw window and text
$0588W $50 $9A $19310E1FRL $83 $C4 $02 $9A $1D060A9BRL
#Wait for key
$9A $14600EDFRL $C7 $06 $7A58W $0063W $C7 $06 $7A5AW $0063W
#Set ammo, flame
$B8 $0001W $5F $5E $8B $E5 $5D $CB